I'd say no. As a shopper, I'm suspicious of marketing gimmicks. I'd be more likely to think the book wasn't so hot because it had a free giveaway. Kudos to the promotional creativity, though. It's a hard market to break into, and definitely worth looking for unconventional marketing ideas.
People are suspicious of FREE. The comic book industry has Free Comic Book Day the first Saturday of May every year. We promote that and set up at local events to draw more people to the stores. I'm amazed when the people want to pay for the free comic books - duh, there are dozens of signs that say "Free". Yes - they are free. No, you don't have to buy anything. No, you don't have to leave your name. No, I don't want your e-mail address. That's right - it's 100% FREE! Well, it's your choice if you don't want to take one. I assure you there is no GPS tracking device in any of the free books.
Yeah, I had to check and see if the cd drive in this computer still opened.
You could give away a code that allows people to get the e-book however they usually get e-books so that way it would be forKindleor the Sony reader or the iPad or whatever they use. When one of my novels came out there was a promotion at Amazon where if you bought the new Elmore Leonard you could get mine for half price. I don't think very many sold.
Jon is right, a great review is still the main thing that sells new books.
NYTBR, WaPo Bookworld, ChiTrib, LA Times (sad remnant of its former self, but still), etc. And that's the whole point, from a reader's perspective--the reviewer/venue does the gatekeeping so I don't have to.
From the writer's point of view, the calculus is pretty grim, you're right. As a debut author, your biggest enemy is obscurity; nobody's ever heard of you, and nobody cares to find out. You're starting out miles and miles behind the last place dog; the little electric bunny of best-seller fame and fortune is completely out of sight. That said, the "trick" to getting reviewer attention as a debut author is to write well, IMO. A sexy hook doesn't hurt, either.